Tilting chair mechanism

ABSTRACT

998,568. Seats. SENG CO. April 30, 1964 [May 15, 1963], No. 17989/64. Heading A4J. A tilting chair mechanism comprises a base 19 having spaced walls 21, 22, Fig. 5, with aligned openings 21a, 22a in which are rotatably mounted supporting means 26 consisting of two relatively rotatable parts 27, 28, a torsion bar 37 being slidably and non-rotatably supported in the supporting means 26 by plugs 35, 36 and bushings 31, 33. A tiltable frame member 42 is welded to part 28 of the supporting means and base 19 is secured to the other part 27 by means of a lever 52 -which is adjustable by a screw 56 to prestress the torsion bar 37.

May 25, 1955 J. R. MEINHARDT 3,185,429

TILTING CHAIR\.`MECHANISM Filed May 15, 196s l' s sheets-sheet 1 May 25, 19.65 n J. R. MElNHARDT 3,185,429

l TILTING CHAIR MEGHANISM 5 Sheets-Sheet 2 Filed May 15, 196:5

May 25 1955 J. R. MEINHARDT TILTINCT CHAIR MECHANISM 5 Sheets-Sheet 5 Filed May l5, 1963 United States Patent O 3,185,429 `TILTING CHAIR MECHANISM James R. Meinhardt, Park Ridge, Ill., assigner to The Seng Company, a corporation of Illinois Filed May 15, 1963, Ser. No. 280,654 12 Claims. (Cl. 248-373) This invention relates to a tilting chair mechanism, and in particular it relates to a torsion bar mechanism for a chair having a fixed base and atilting portion.

Tilting `chair mechanismswhich utilize a torsion` bar to control the tilt of a unitary seat and back rest, or of a back rest associated with a fixed seat, have numerous advantages of compactness, clean, attractive appearance, and elimination of Vmoving parts; but, conversely, they are difficult to assemble, and if a torsion bar breaks the `construction is such as to require replacement of the entire tilting mechanism;

The principal object of the present invention, therefore, is to provide a torsion bar tilting chair mechanism which is easy to assemble, and in which the torsion bar may be removed endwise from a supporting means in which it is nonrotatably carried.

Yet another object of the invention is to provide a tilting chair mechanism which requires a minimum of welding in its assembly.

Still another object of the invention is to provide a tilting chair mechanism which, except for the torsion bar, may be entirely fabricated from metal stampings, and bushings cast from powdered metal or formed from nylon.

The invention is illustrated in a preferred embodiment in the accompanying drawings in which:

FIG. 1 is a side elevational view of an oiiice chair provided with the tilting chair mechanism of the present invention;

FIG. 2 is a longitudinal central sectional view of the tilting mechanism, taken substantially as indicated along the line 2-2 of FIG. 4;

FIG. 2A is an enlarged fragmentary section like a portion of FIG. 2;

FIG. 3 is a horizontal sectional view taken substantially as indicated along the line 3-3 of FIG. 2;

FIG. 4 is a front elevation-al view taken substantially as indicated along the line 4--4 of FIG. 3;

FIG. 5 is a transverse central sectional view on an enlarged scale taken substantially as indicated along the line 55 of FIG. 2;

FIG. 6 is a sectional view taken substantially `as indicated along the line 6 6 of'FIG. 5;

FIG. 7 is a `sectional view taken substantially as indicated along the line 7-7 of FIG. 5;

`the subject of the present invention, and a chair, indicated generally at 15, that includes a seat 16 secured to the tilting mechanism 14, with fixed arms 17 and a fixed back 18 fixed to the chair seat.

Referring now particularly to FIGS. 2 to 5 inclusive, the spindle assembly 13 is surmounted by a base, indicated generally` at 19, which includes a transverse web 20 riveted to the top of the spindle assembly and longitudinal upright `walls 21 and 22 at the extremities of the base. The wall 21 has an aperture 21a, while the wall 22 has a slightly larger aperture 22a. The base 19 also includes an inice `parts in the form of an elongated first tube 27 and a shorter second tube 28. The tube 27 makes an easy rotating fit in the smaller wall opening 21a, while an outer bushing 29 in the larger Wall opening 22a. affords an easy rotating fit for an end of the tube 27, and a circumferential flange 38 on the bushing abuts the outer face of thewall 22 to provide a spacer. An inner bushing 31 fits in the end of tube 27 and has a circumferential flange 32 that overlies the end of the tube and makes an easy rotating fit within the outer bushing 29; While an identical inner bushing 33 occupies the adjacent end of the second tube 28 and has a circumferential flange 34 overlying the end of tube 28 and abutting the flange 32 of the internal bushing 31. The bushing flange 34 also makes an easy rotating fit within the outer bushing 29 so that the second tube 28 is centered in the opening 22a and rotatable in the bushing.

In the outer end of tube 27 is a fixed plug 35, while an identical plug 36 is fixed in the outer end of tube 28, conveniently by welding. The plugs 35 and 36 and the inner bushings 31 and 33 are provided, respectively, with noncircular axial openings 35a, 36a, 31a, and 33a; and a non circular torsion bar 37 the cross section of which is identical with the shape of said opennigs 35a, etc., is nonrotatably mounted for endwise sliding movement in said plugs and said bushings. A pair of friction end caps 38 and 39 (see FIG. 6) have inwardly extending spring fingers 40 and 41, respectively, which frictionally grip end portions 37a and 37b of the torsion bar which project, respectively, from the plugs 35 and 36. Thus, the friction caps lock the torsion bar 37 against endwise movement and retain it in the torsion bar supporting means 26.

The chair 15 is mounted for tilting movement about the axis of the torsion bar by a tilting frame member, in the form of a spider 42 having an upright fiange 43 with a hole 43a to receive the inner end of the tube 28, and the fiange 43 is secured to the tube 28 by a weld 43b. The spider 42 also has a horizontal flange 44 to which the chair seat 16 is screwed. A second spider 45 has an upright flange 46 with an aperture 47 by means of which said spider 45 is journalled upon a second outer bushing 48 that has a circumferential flange 49 abutting the outer face of the spider flange 46. A spacer washer 50 also surrounds the Vouter bushing 48 between the base wall 21 and the spider flange 46. The assembly is completed by releasable means in the form of a friction retaining Washer '51 that grips the tube 27` and abuts the outer bushing flange 49 so as to clamp bushing 48, second spider 45 and spacer 50 against wall 21.

As seen in FIGS. 7, 8 and 9, the outer bushings 29 and 48 have radially extending lugs 29a and 48a, respectively, which seat in complementary notches in the base Wall 22 and the spider flange 46, respectively, to lock said outer bushings against rotation. The outer bushings 29 and 48, the inner bushings 31 and 33, and the fixed plugs 35 and 36 may all be conveniently and inexpensively fabricated either by casting from powdered metal or by molding from nylon.

The tube 27 is adjustably secured to base 19 by means of a yokelike adjusting lever 52 having a transverse top lplate 53 and parallel depending legs 54 which loosely embrace a central portion of the tube 27. A portion 27a of the tube between the legs 54 is flattened, and a rectan gular key 55 is driven between the attened portion 27a of the tube and the top plate 53 of the lever to detachably secure the lever on the tube. As best seen in FIG. 2, the

top plate 53 extends forwardly above the inclined front wall portion 23 of the base 19, and an adjusting screw 56 that has a T-head 57 seated in a transverse slot 53a in the top plate 53 and in connecting notches 54a in the legs 54 has a threaded shank extending through an opening 23a in the inclined wall 23 to receive a nut 58 having a finger piece 59 so that the nut may be easily rotated on the bolt to adjust the position of the lever 52 with respect to the base 19 .and thus prestress the torque bar 37.

It is apparent from the foregoing detailed description that the present invention affords a very simple and inexpensive torsion bar tilting chair mechanism which is easily assembled, and in which the torsion bar may be readily removed and replaced. The assembly has a total of 20 parts (disregarding rivets for mounting it on the spindle assembly), of which all but the torsion bar are metal stampings, powdered metal castings, molded nylon parts, or commercially available articles. The only welding is to secure the plugs 35 and 36 into the ends of the tubes 27 and 28, and to fasten the first spider 42 to the tube 28.

After the base 19 is riveted onto the head of spindle assembly 13 and the plugs 35 and 36 and spider 42 are welded into place, the mechanism is assembled as follows: The outer bushing 29 is positioned in the wall opening 22a, the inner bushings 31 and 33 are placed in the ends of the tubes 27 and 28, respectively, the torque bar 37 is slid endwise entirely through the two tubes, the lever 52 is held while the tube 27 is slid through the hole 21a, the lever legs 54 and into the outer bushing 29, the outer bushing 48 is placed in the opening 47 of the spider flange 46, the spacer 50 is mounted on the projecting end of the bushing 48 the sub-assembly of bushing 4S, spider 45 and spacer 50 is slid onto the tube and into abutment with the wall 21, the friction washer 51 is driven into place on the tube, the tube 28 is slid over the torsion bar to position the inner bushing ange 33 in the outer bushing 29, the friction caps 38 and 39 are driven onto the ends of the torsion bar 37, the adjusting lever 52 is oriented on the tube 27 with the top plate 53 adjacent the flat 27a on the tube, and the key 55 is driven in to fix the lever in place. The T-bolt is then dropped into place and the nut 58 screwed onto it to complete the assembly. The entire operation is very rapid and requires a minimum of equipment. Furthermore, the whole mechanism may be readily disassembled and reassembled using only a thin blade to pry off the friction caps 38 and 39 and the friction washer S1, and a hammer to loosen the bushings and replace the friction caps and washer. In particular a torsion bar 37 may be removed and replaced merely by t prying off the friction caps 38 and 39. They may be driven back on with a hammer.

The foregoing detailed description is given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, as some modifications will be obvious to those skilled in the art.

I claim:

l. A tilting chair mechanism comprising, in combination: a base having a transverse web with a pair of parallel longitudinal upright walls, there being aligned openings in said Walls; elongated torsion bar supporting means rotatably mounted in said openings, said supporting means having first and second relatively rotatable parts which are axially aligned and longitudinally slidably mounted in the openings; releasable means retaining the first part of said supporting means against longitudinal sliding movement; fixed plugs at opposite ends of said supporting means, said plugs having aligned non-circular openings; a torsion bar slidably and nonrotatably supported in said plug openings for endwise removal from the supporting means, said bar having its end portions projecting from the ends of the supporting means; removable retaining means engaging said end portions of the bar to retain it in the supporting means, said removable retaining means and torsion bar cooperating to retain the second path of the supporting means against longitudinal sliding movement; means securing a tilting frame member to the second part of the supporting means; and means securing the base to said first part of said supporting means, one of said two last named means being adjustable to adjustably prestress the torsion bar.

2. The mechanism of claim l in which the supporting means comprises a pair of axially aligned tubes.

3. The mechanism of claim 2 in which a first of said tubes extends throughra first Wall of the base and terminates substantially at a second wall of the base, the second tube has an end centered in the opening in said second wall and extends outwardly therefrom, and the tilting frame member is secured to said second tube immediately outside said second wall.

4. The mechanism of claim 3 which includes an outer bushing in the opening in said second wall; said outer bushing having a circumferential flange spacing said wall from the tilting frame member, a first inner bushing in the first tube which embraces the torsion bar and has a circumferential flange snugly rotatable in the outer bushing, and a second inner bushing in the second tube which embraces the torsion bar and has a circumferential flange abutting that of the first inner bushing and snugly rotatable in the outer bushing.

5. The device of claim 1 in which the adjustable means is a lever fixed centrally on the supporting means above the web, and screw means engaging the lever and the web.

6. The device of claim 5 in which the supporting means is a tube that has a fiattened central portion, the adjusting lever is freely rotatable on the tube about said fiattened portion, and a key driven between a portion of the lever and said flattened portion of the tube releasably fixes the lever on the tube.

7. The device of claim 1 in which a first part of the torsion bar supporting means is a first tube slidably supported in both walls of the base, said tube being held against sliding movement in one direction by the releasable means and being held against sliding movement in the other direction by the retaining means on the 0pposite end of the torsion bar, and a second part of the supporting means is a second tube having an internal rotatable bushing that embraces the torsion bar and abuts an end of the first tube, said second tube being retained against linear movement by the tilting frame member and the retaining means on the torsion bar.`

8. The mechanism of claim 1 in which the tilting frame member is a seat spider secured to said one part of the supporting means immediately outside one of the base walls, and a second spider is rotatably mounted on said other part .of the supporting means immediately outside the other of the base walls.

9. A tilting chair mechanism comprising, in combination, a base having a transverse web with first and second longitudinal upright walls, there being aligned openings in said walls; an elongated tube rotatably mounted in said openings, said tube having a first end portion extending outwardly from the first wall and a second end portion terminating substantially at the second wall; a first plug in said first end of the tube, said plug having a non-circular axial opening; a first rotatable bushing in the second end of the tube, said bushing having an axial opening identical with that in the plug; a torsion bar having a first end slidably and nonrotatably carried in said plug, said torsion bar extending slidably and nonrotatably through the bushing and having a second end a substantial distance outwardly of said bushing; a first seat spider rotatably supported on the first end portion of the tube immediately outside said first wall; friction means engaging the tube to confine the first spider adjacent said first wall; a second seat spider; a short tube fixedly secured to said second spider and aligned with the elongated tube; a second rotatable bushing in said short tube and having a fiange adjacent the second spider and centered in the opening in the second wall, said bushing having a non-circular opening slidably embracing the torsion bar; a second plug fixed in the outer end ofthe short tube, said plug having a non-circular axial Vopening slidably embracing the torsion bar, the end portions of the torsion bar extending slightly outwardly of both said plugs; retaining caps frictionally engaging said end portions of the torsion bar to retain it in said tubes; an adjusting lever xedly secured to the elongated tube between said Walls; and means adjustably engaging said lever and the transverse web to adjustably prestress the torsion bar.

10. The device of claim 9 in which the tube has a attened central portion, the adjusting lever is freely rotatable on the tube about said flattened portion, and a key driven between a portion of the lever and said flattened portion of the tube releasably xes the lever on the tube. r

11. The device of claim 9 which includes a rst outer bushing centering the elongated tube in the rst spider, a second outer bushing centering the elongated tube in the second wall, and in which the second bushing has its ange in said second outer bushing.

l2. A tilting chair mechanism comprising in combination: a base having a transverse web with first and second parallel longitudinal upright walls, there being aligned openings in said walls; elongated torsion bar supporting means rotatably and longitudinally slidably mounted in said openings, said supporting means having rst and second axially aligned, relatively rotatable parts the irst of which projects a substantial` distance transversely outside the first wall and has an open end substantially in the second Wall, and `the second of which projects a substantial distance transversely outside the second Wall and has an open end substantially in the second wall facing the open end of the first part; releasable means retaining the rst part of said supporting means against longitudinal sliding movement; xed plugs at opposite ends of said supporting means, said plugs having aligned noncircular openings; a torsion bar slidably and nonrotatably supported in said plug openings :for endiwise removal from the supporting means, said bar having its end portions projecting from the ends of the supporting means; removable retaining means engaging said end portions of the bar to retain it in the supporting means, said removable retaining means and torsion bar cooperating to retain the second path of the supporting means against longitudinal sliding movement; means securing a tilting frame member to the second part of the supporting means; and means securing the base to said rst part of said supporting means, one of said two last named means being adjustable to adjustably prestress the torsion bar.

References Cited bythe Examiner UNITED STATES PATENTS 2,760,553 8/56 Lie 248-373 2,971,569 2/ 61 Parrott et al. 248-373 3,072,377 1/ 63 Blomberg 248-373 References Cited by the Applicant UNITED STATES PATENTS 2,718,257 9/55 Lie.

CLAUDE A. LE ROY, Primary Examiner. 

1. A TILTING CHAIR MECHANISM COMPRISING, IN COMBINATION: A BASE HAVING A TRANSVERSE WEB WITH A PAIR OF PARALLEL LONGITUDINAL UPRIGHT WALLS, THERE BEING ALIGNED OPENING IN SAID WALLS; ELONGATED TORSION BAR SUPPORTING MEANS ROTATABLY MOUNTED IN SAID OPENINGS, SAID SUPPORTING MEANS HAVING FIRST AND SECOND RELATIVELY ROTATABLE PARTS WHICH ARE AXIALLY ALIGNED AND LONGITUDINALLY SLIDABLY MOUNTED IN THE OPENINGS; RELEASABLE MEANS RETAINING THE FIRST PART OF SAID SUPPORTING MEANS AGAINST LONGITUDINAL SLIDING MOVEMENT; FIXED PLUGS AT OPPOSITE ENDS OF SAID SUPPORTING MEANS, SAID PLUGS HAVING ALIGNED NON-CIRCULAR OPENINGS; A TORSION BAR SLIDABLY AND NONROTATABLY SUPPORTED IN SAID PLUG OPENINGS FOR ENDWISE REMOVAL FROM THE SUPPORTING MEANS, SAID BAR HAVING ITS END PORTIONS PROJECTING FROM THE ENDS OF THE SUPPORTING MEANS; REMOVABLE RETAINING 